@Pragi,
Greetings! I have the GR5 Demo (which I can't Update as I don't have the Service Center app) and so just purchased GR 7, but I prefer the 5 interface. I use MacOS. Do you still happen to have a 5 Installer and, if so, is the OSX or Windows version? IF Mac, could we arrange for you to email me?
Thanks either way and Best Regards and Best Wishes!